1. Field of the Invention
The present invention relates to an oil-containing waste water treating material which is effective in treating cleaning oil fractions, sewage or factory waste water containing various oil fraction mixtures and solids.
2. Description of the Prior Art
Many oil-water separating methods are known for the treatment of oil-containing waste water. For example, in one conventional technique applied to crude waste water which contains oil fractions comparatively easy to separate by a physical process, the waste water is filtered with sand to reduce the load on an active carbon adsorbent, is then passed through active carbon to adsorb oil thereon and is drained. If further processing is desirable, the waste water, after filtration over the sand bed and before contact with active carbon, is charged into a tower containing synthetic fibers having an affinity for oil, and the water discharged from the tower is then sent to the active carbon filtration zone. However, because of recent, more stringent regulations concerning the draining of waste water, the conventional active carbon treatment processes are insufficient in removing oil fractions from waste water to the required degree, and therefore, higher levels of treatment of waste water are required. This need is heightened by the fact that clean water itself is a valuable resource and therefore with efficient purification, waste water can serve as a source for pure water. On the other hand, in the instances of waste waters containing oil fractions which are difficult to remove such as those containing emulsified oil, a method is needed by which oil can be removed with a high degree of effectiveness. Therefore, a need continues to exist for an improved technique of removing contaminating oil fractions from various types of waste waters.